Semiconductor device with improved immunity to contact and conductor defects

ABSTRACT

In a semiconductor device, an impurity diffused layer serving as an active region is formed in a predetermined region of the surface of a semiconductor substrate of silicon, an underlayer insulating film is formed on the semiconductor substrate for the purpose of protecting and stabilizing the surface of the semiconductor substrate, and an interconnection electrically connected to the impurity diffused layer through a contact hole and formed on an Al-Si-Sn alloy, an Al-Si-Sb alloy or alloys having Ti added to the respective alloys, so that occurrence of an alloy pit and a silicon nodule is prevented. In addition, a completed protective film is formed on the interconnection and the underlayer insulating film and an aperture in a bonding pad region is formed in a predetermined region of the completed protective film, so that the interconnection and the bonding pad are electrically connected to each other. The proportion of silicon and other materials in the alloy are controlled to simultaneously avoid alloy pit and silicon nodule defects both at the contact hole and throughout the alloy conductor.

This application is a continuation; application of application Ser. No.07/249,906, filed Sep. 27, 1988, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to semiconductor devices, andmore particularly, to an improvement of the material composition of afilm of an aluminum alloy used as an interconnection of thesemiconductor device.

2. Description of the Prior Art

Conventionally, as materials most widely used as an interconnection of asemiconductor device, an aluminum-silicon alloy (referred to as Al-Sialloy) containing approximately 1.0 to 2.0% silicon by weight has beenknown.

FIG. 1 is a cross sectional view showing a schematic structure of theconventional semiconductor device using the Al-Si alloy as aninterconnection material. In FIG. 1, the conventional semiconductordevice comprises an impurity diffused layer 2 formed in a predeterminedregion of the surface of a semiconductor substrate 1 of silicon, anunderlayer insulating film 3 formed for the purpose of protecting andstabilizing the surface of the semiconductor substrate 1, aninterconnection 5 of the Al-Si alloy (referred to as Al-Siinterconnection hereinafter) formed in a predetermined region on theunderlayer insulating film 3 and electrically connected to the impuritydiffused layer 2 through a contact hole 4, and a completed protectivefilm 6 formed on the Al-Si interconnection 5 and the underlayerinsulating film 3 for the purpose of protecting the surface of thesemiconductor device. A contact hole 7 is formed in a predeterminedregion of the completed protective film 6. The region having the contacthole 7 formed therein becomes a bonding pad region for electricallyconnecting the Al-Si interconnection 5 to the exterior.

FIGS. 2A to 2D are cross sectional views showing steps of forming aninterconnection in the conventional semiconductor device using the Al-Sialloy shown in FIG. 1 as an interconnection material. Referring now toFIGS. 2A to 2D, description is made on a method for manufacturing theconventional semiconductor device.

In FIG. 2A, an impurity diffused layer 2 serving as an active region isformed in a predetermined region of the surface of a semiconductorsubstrate 1 using photolithographic techniques, an ion implantationprocess or the like. An underlayer insulating film 3 comprising a PSG(Phospho-Silicate Glass) film or the like is then deposited on theexposed entire surface using a CVD process for the purpose of protectingand stabilizing the surface of the semiconductor substrate 1. A contacthole 4 is then formed in a predetermined region of the underlayerinsulating film 3 using photolithographic and etching techniques inorder to make electrical contact to the impurity diffused layer 2.

In FIG. 2B, after a film of an Al-Si alloy is deposited on the exposedentire surface using a spattering process, a vacuum evaporation processor the like, an Al-Si interconnection 5 having a desired shape is formedusing photolithographic and etching techniques.

In FIG. 2C, in order to obtain good ohmic contact between theinterconnection 5 and the impurity diffused layer 2, heat treatment isperformed for several ten minutes at a temperature of 400° to 500° C. inan atmosphere of hydrogen or oxygen, to cause an eutectic reaction inthe interface of the Al-Si interconnection in the contact hole 4 and thesemiconductor substrate.

In FIG. 2D, an insulating film such as a silicon oxide film, a PSG filmand a silicon nitride film is deposited on the exposed entire surface asthe completed protective film 6 using a CVD process. Then, in order toelectrically connect the semiconductor device (Al-Si interconnection) tothe exterior, a contact hole 7 is formed in a predetermined region ofthe completed protective film 6 using photolithographic and etchingtechniques. The region having the contact hole 7 formed therein becomesa bonding pad region.

FIG. 3 is a schematic cross sectional view of a semiconductor deviceusing a simple substance of aluminum as an interconnection material.

When the simple substance of aluminum (pure aluminum) is used as aninterconnection material, there is a phenomenon that in a heat-treatingprocess at a temperature of 400° to 500° C. for forming good ohmiccontact between an interconnection 10 of pure aluminum and an impuritydiffused layer 2, silicon in the impurity diffused layer 2 and aluminumincluded in the interconnection 10 of pure aluminum locally react witheach other in a contact hole region 4, so that an alloy pit 11 occurs,as shown in FIG. 3. This is not a problem when the depth of the impuritydiffused layer 2 is large. However, the finer the semiconductor deviceis made, the smaller the depth of the impurity diffused layer 2 becomes,i.e., 0.5 μm or less. Thus, this alloy pit 11 penetrates through theimpurity diffused layer 2, so that a punch-through region 12 in theimpurity diffused layer 2 is formed, whereby the interconnection 10 andthe semiconductor substrate 1 are short-circuited. This reaction betweensilicon and aluminum takes place by the mechanism that at the time ofheat treatment at a temperature of 400° to 500° C., the silicon in theimpurity diffused layer 2 dissolves in the interconnection 10 of purealuminum and the aluminum enters the impurity diffused layer 2 by mutualdiffusion.

Conventionally, an interconnection of an Al-Si alloy having siliconpreviously added thereto in excess of the limit of silicon solubility toaluminum in the vicinity of a temperature of heat treatment, as shown inFIG. 1, has been widely used as one of the measures to preventoccurrence of this alloy pit 11.

The solid solubility (the limit of solid solubility) of silicon toaluminum is 0.25% by weight at a temperature of 400° C., 0.5% by weightat a temperature of 450° C. and 0.8% by weight at a temperature of 500°C. The major trend is that the content of silicon in the Al-Si alloywhich has been put into practice is slightly higher than the abovedescribed solid solubility, i.e., approximately 1.0 to 2.0% by weight.

However, even if the Al-Si alloy is used as an interconnection materialas described above, the integration density of the semiconductor deviceis increased. Thus, as the size of a device is made finer to enter asubmicron region, two large problems occur in the conventional Al-Siinterconnection. More specifically, occurrence of the alloy pit in thecontact hole region 4 can be prevented in heat treatment at atemperature of 400° to 500° C. performed after forming the Al-Siinterconnection 5, as shown in FIG. 2C. However, other two defectivemodes appear.

One of the defective modes is a silicon deposition phenomenon thatsilicon included in the Al-Si interconnection 5 is deposited in excessin the contact hole region 4 by solid phase epitaxial growth in whichsubstrate silicon serves as a seed crystal at the time of heattreatment. This deposited silicon 8 is close to an intrinsicsemiconductor and has a very high specific resistance value. Thus, ifsilicon is deposited in a part or all of the contact hole 4 at asubmicron level, contact resistance between the interconnection 5 andthe impurity diffused layer 2 becomes very high, so that electricalfailures occur.

The other defective mode is a phenomenon that silicon included in theAl-Si interconnection 5 in excess is deposited in the interconnection ata submicron level, so that a mass referred to as a silicon nodule 9 isformed. This silicon nodule 9 is close to an intrinsic semiconductor andhas a very high specific resistance value. In addition, since thesilicon nodule grows to the size of approximately 1 μm, across-sectional area of an effective interconnection is locallydecreased. Thus, the current density in this portion is substantiallyincreased, so that failures such as generation of heat byelectromigration and disconnection are liable to occur.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to solve the abovedescribed problems and to prevent deposition of silicon included in aninterconnection of an aluminum alloy into a contact hole portion andoccurrence of a silicon nodule in the interconnection, thereby toprovide a stable and reliable semiconductor device.

The semiconductor device according to the present invention uses analloy having at least one type of element different from silicon in thesame group, in the periodic table, as that of an element constituting asemiconductor substrate added to aluminum as an interconnectionmaterial. In addition, the content of silicon in the interconnectionmaterial is suppressed to less than the solid solubility to aluminum atthe time of heat treatment at a temperature of 400° to 500° C.

Since the content of silicon in the interconnection material accordingto the present invention is made to be less than the solid solubility,occurrence of the silicon nodule and deposition of silicon into thecontact hole portion at the time of heat treatment are suppressed. Inaddition, the content of silicon in an interconnection of an aluminumalloy is decreased. However, the interconnection includes at least onetype of element different from silicon in the same group, in theperiodic table, as that of an element constituting a semiconductorsubstrate, so that the silicon in an impurity diffused layer is notsoluble in the interconnection layer of an aluminum alloy film. Thus,aluminum does not diffuse into the impurity diffused layer, so thatoccurrence of an alloy pit can be prevented.

In a more preferred embodiment, a semiconductor substrate is formed ofsilicon, and at least one type of element in a group consisting ofcarbon, tin and lead is added to an interconnection layer of an aluminumalloy film. In addition, the interconnection layer of an aluminum alloycontains silicon. The content x of silicon is selected to satisfy 0≦x0.8 wt.%, and the content y of elements excluding the silicon in thesame group is selected to satisfy 0.2≦y ≦2.0 wt.%, and x and y areselected to satisfy x+y≦2.0 wt.%.

Still more preferably, one type of titanium, vanadium and chromium isadded to an interconnection layer of an aluminum alloy film as anelement having strong bond force to oxygen, the total amount z thereofbeing selected to satisfy 0.05≦z≦1.0 wt.%.

According to another aspect of the invention, the content of silicon inan interconnection material is decreased to less than the limit of solidsolubility of silicon to aluminum when a temperature of heat treatmentis reached, and at least one type of element in a group adjacent, in theperiodic table, to that of an element constituting a semiconductorsubstrate is added in small quantities.

Thus, according to this other aspect of the invention, at least one typeof element similar to silicon in physical and chemical properties and ina group adjacent, in the periodic table, to that of silicon, silicon inan impurity diffused layer can not be soluble in an aluminum alloy, sothat occurrence of an alloy pit can be prevented.

In a more preferred embodiment, at least one type of element in a groupconsisting of boron, gallium, indium, thallium, phosphorus, arsenic,antimony and bismuth is added to an aluminum alloy film. In addition,silicon is contained in the aluminum alloy film. The content x ofsilicon is selected to satisfy 0≦x≦0.8 wt.% and the total amount y ofaddition of an element in an adjacent group is selected to satisfy0.2≦y≦2.0 wt.%, and x and y are selected to satisfy x+y≦2.0 wt.%

Additionally, one type of element out of titanium, vanadium and chromiumis added to an interconnection layer of an aluminum alloy film as anelement having strong bond force to oxygen, the total amount z thereofbeing selected to satisfy 0.05≦z≦1.0 wt.%.

These objects and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a schematic cross-sectional structure of aconventional semiconductor device;

FIGS. 2A to 2D are cross-sectional views showing steps of a method forforming an interconnection in the conventional semiconductor deviceusing an Al-Si interconnection;

FIG. 3 is a diagram showing a schematic cross-sectional structure of theconventional semiconductor device using an interconnection of purealuminum;

FIG. 4 is a cross-sectional view showing a schematic structure of asemiconductor device according to one embodiment of the presentinvention;

FIGS. 5A to 5D are cross-sectional views showing the steps of forming aninterconnection of the semiconductor device according to one embodimentof the present invention; and

FIG. 6 is a diagram showing a schematic cross-sectional structure of asemiconductor device according to another embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4 is a diagram showing a schematic cross-sectional structure of acontact hole portion of a semiconductor device according to oneembodiment of the present invention. In FIG. 4, the semiconductor deviceaccording to one embodiment of the present invention comprises asemiconductor substrate 1 of silicon, an impurity diffused layer 2formed in a predetermined region of the surface of the semiconductorsubstrate 1 to serve as an active region, an underlayer insulating film3 formed to protect and stabilize the surface of the semiconductorsubstrate 1, an interconnection 21 electrically connected to theimpurity diffused layer 2 through a contact hole 4 and formed of anAl-Si-Sn alloy which can prevent occurrence of an alloy pit and asilicon nodule, and a completed protective film 6 formed on theinterconnection 21 and the underlayer insulating film 3, and an aperture7 in a bonding pad region formed in a predetermined region of thecompleted protective film 6 for electrically connecting theinterconnection 21 to the exterior.

FIGS. 5A to 5D are cross-sectional views showing the steps of a methodfor forming an interconnection of the semiconductor device according toone embodiment of the present invention. Referring now to FIGS. 5A to5D, description is made on the method for forming an interconnection ofthe semiconductor device according to one embodiment of the presentinvention.

In FIG. 5A, in the same manner as the conventional example, an impuritydiffused layer 2 serving as an active region is formed in apredetermined region of the surface of a semiconductor substrate 1 ofsilicon using photolithographic techniques, an ion implantation processand the like. An underlayer insulating film 3 comprising a PSG film orthe like is then formed for the purpose of stabilizing and protectingthe surface of the semiconductor substrate 1. A contact hole 4 formaking electrical connection to the impurity diffused layer 2 is thenformed in a predetermined region of the underlayer insulating film 3using photolithographic and etching techniques.

In FIG. 5B, after a film of an Al-Si-Sn alloy is deposited on theexposed entire surface using a sputtering process, a vacuum evaporationprocess or the like and then, an Al-Si-Sn interconnection 21 having adesired shape is formed using photolithographic and etching techniques.

In order to prevent deposition of silicon in a contact hole portion andoccurrence of a silicon nodule in the interconnection 21 at the time ofheat treatment at a temperature of 400° to 500° C. in the followingstep, the content of silicon in the Al-Si-Sn interconnection 21 is setto a value of not more than solid solubility (the limit of solidsolubility) of silicon to aluminum in a region at this temperature,i.e., 0 to 0.8% by weight. Considering a case in which heat treatment ata temperature of 400° to 500° C. is performed for achieving good ohmiccontact in the following process, even if the content of silicon isdecreased, silicon in the impurity diffused layer 2 is soluble in theinterconnection, so that the above described alloy pit occurs in theimpurity diffused layer 2.

In order to prevent the silicon in the impurity diffused layer 2 frombeing soluble in the interconnection, tin in the same group, in theperiodic table, as that of silicon which is a constituent element of thesemiconductor substrate 1 is added. The effect is obtained when theamount of addition of tin for preventing occurrence of the alloy pit isapproximately 0.2 to 2.0% by weight depending on the content of siliconin the interconnection 21. However, the sum x+y of the amount x ofaddition of silicon and the amount y of addition of tin is set to 2.0%by weight or less in order to prevent deposition of silicon. Inaddition, tin is an element which has a property physically similar tosilicon but is different from silicon. Thus, tin suppresses depositionof silicon in the contact hole 4 due to solid phase epitaxial growth ofsilicon. Consequently, in this respect, addition of tin is effective. Inaddition, tin is an element in the same group as that of silicon and tinis similar to silicon in physical and chemical properties. Thus, tindoes not constitute a movable ion, so that tin does not adversely affectdevice characteristics.

In FIG. 5C, in order to make good ohmic contact of the interconnection21 to the impurity diffused layer 2, heat treatment is performed forseveral tens of minutes at a temperature of 400° to 500° C. in anatmosphere of nitrogen or hydrogen, to cause an eutectic reaction in theinterface of the Al-Si-Sn interconnection 21 and the impurity diffusedlayer 2. On this occasion, since the content of silicon in theinterconnection 21 is maintained at less than the limit of solidsolubility, silicon is not deposited by solid phase epitaxial growth andno silicon nodule occurs. In addition, since silicon and tin are addedsuch that the sum thereof is more than the limit of solid solubility ina region at this temperature, silicon in the impurity diffused layer 2does not dissolve into the interconnection 21, so that no alloy pitoccurs.

In FIG. 5D, an insulating film such as a silicon oxide film, a PSG film,a silicon nitride film is deposited on the exposed entire surface as acompleted protective film 6 using a CVD process and then, an aperture 7in a bonding pad region for electrically connecting the interconnection21 to the exterior is formed in a predetermined region of the completedprotective film 6 using photolithographic and etching techniques.

Although in the above described embodiment, description was made on acase in which tin is added as an element in the same group, in theperiodic table, as that of silicon which is an element constituting asemiconductor substrate is used as an interconnection material, anotherelement in the same group, i.e., carbon and lead may be added. Also inthis case, the element of 0.2 to 2.0% by weight may be added dependingon the content of silicon in the interconnection, to obtain the sameeffect as that of the above described embodiment.

Additionally, although in the above described embodiment, a ternaryalloy having one type of element different from silicon in the samegroup as that of an element constituting a semiconductor substrate addedto an Al-Si alloy is used as an interconnection material, an alloyincluding multiple elements having a plurality of elements in the samegroup added thereto may be used as an interconnection material. In thiscase, the total amount of addition of the elements in the same group maybe 0.2 to 2.0% by weight depending on the content of silicon in aninterconnection, to obtain the same effect as that of the abovedescribed embodiment.

Additionally, silicon need not be added. For example, a binary alloyhaving at least one type of element different from silicon in the samegroup as that of an element constituting a semiconductor substrate or analloy including multiple elements added to pure aluminum may be used asan interconnection material, to obtain the same effect as that of theabove described embodiment.

As described in the foregoing, according to one embodiment of thepresent invention, since an aluminum alloy having a reduced content ofsilicon in a simple substance of aluminum or an Al-Si alloy and havingat least one type of element different from silicon in the same group asthat of an element constituting a semiconductor substrate added theretowas used as an interconnection material in the semiconductor device,occurrence of an alloy pit and deposition of silicon in a contact holeportion and occurrence of a silicon nodule in the interconnection in aheat-treating process after forming an interconnection of an aluminumalloy can be prevented and an electrical short between theinterconnection layer and the semiconductor substrate due to a punchthrough phenomenon of an impurity diffused layer, the increase incontact resistance, the decrease in electromigration resistance and thelike can be prevented, whereby a stable and reliable semiconductordevice can be achieved.

In another embodiment of the present invention, a small quantity ofantimony similar to silicon in physical and chemical properties, i.e.,an element in a group adjacent, in the periodic table, to that ofsilicon is added in order to suppress the solubility of silicon from animpurity diffused layer 2 into an interconnection. The effect isobtained when the amount of addition of antimony for preventingoccurrence of an alloy pit is approximately 0.2 to 2.0% by weightdepending on the content of silicon in the interconnection of an alloy.More specifically, the sum of the content of silicon in aninterconnection of an alloy and the content of antimony is preferablyset to 1.0 to 2.0% by weight.

In this case, if a too large quantity of antimony is added, new problemsoccur. For example, interconnection resistance is increased, and siliconis deposited. In addition, since antimony is an element physicallysimilar to silicon but different from silicon, silicon is not depositedin a contact hole portion 4 by solid phase epitaxial growth in whichsubstrate silicon is used as a seed crystal. In this respect, antimonyis an effective element. In addition, since the degree of deposition ofantimony is negligible, as compared with that of silicon and antimonydoes not be a movable ion, antimony added in small quantities does notadversely affect device characteristics.

In a manufacturing method according to the present embodiment, a film ofan Al-Si-Sb alloy is deposited on the underlayer insulating film 3 andthe contact hole 4 using a spattering process, a vacuum evaporationprocess or the like, in FIG. 5B in the above described embodiment. Onthis occasion, the content of silicon in the film of an alloy is 0 to0.8% by weight, and the content of antimony therein is approximately 0.2to 2.0% by weight depending on the content of silicon. The film of anAl-Si-Sb alloy is then patterned in a predetermined shape usingphotolithographic and etching techniques, so that an Al-Si-Sbinterconnection 21 is formed.

Then, processing shown in FIG. 5C is performed, which is the same asthat in the above described embodiment. In FIG. 5C, since the content ofsilicon in the interconnection 21 is decreased to less than the solidsolubility in a region at the temperature and a small quantity ofantimony which is similar in physical and chemical properties to siliconis added, silicon is not deposited in the contact hole portion 4 bysolid phase epitaxial growth and no silicon nodule occurs in theinterconnection 21. Processing shown in FIG. 5D is the same as that inthe above described embodiment.

Although in the above described embodiment, description was made on acase in which antimony is used as an element added to theinterconnection 21 of an alloy, any of boron, gallium, indium, thallium,phosphorus, arsenic, antimony and bismuth which are other elements maybe used, to obtain the same effect as that in the above describedembodiment can be obtained. Also in this case, the element of 0.2 to2.0% by weight may be added depending on the content of silicon in theinterconnection of an alloy, to obtain the same effect.

Furthermore, although in the above described embodiment, description wasmade on a case in which a ternary alloy having one kind of element in agroup adjacent to that of silicon added to an Al-Si alloy, an alloyincluding multiple elements having a plurality of elements in theadjacent group added thereto may be used. In this case, the total amountof the added elements excluding silicon may be 0.2 to 2.0% by weight, toobtain the same effect.

Additionally, silicon need not be added. For example, a binary alloyhaving one type of element in Group III or V added to pure aluminum andan alloy including multiple elements having a plurality of types ofelements in Groups III and V without adding silicon may be used as aninterconnection material, to obtain the same effect.

According to the above described embodiment, when one kind of element ora plurality of kinds of elements in the same or the adjacent group, inthe periodic table, as or to the element constituting the semiconductorsubstrate are added in order to decrease the solid solubility ofsilicon, deposition of the silicon 8 into the contact hole portion 4 anddeposition of the silicon nodule 9 into the interconnection layer 5 canbe prevented, respectively. On the other hand, when adhesion of the PSGfilm or the like to the underlayer insulating film 3 is prevented,resulting in wire bonding, the interface of the interconnection layerportion 5 in the aperture 7 in the bonding pad region 5 and theunderlayer insulating film 3 is liable to be stripped off. Descriptionis now made on an embodiment in which such a problem is solved.

FIG. 6 is a diagram showing a schematic cross-sectional structure of asemiconductor device according to another embodiment of the presentinvention. The embodiment shown in FIG. 6 is the same as the abovedescribed embodiment shown in FIG. 4 except that the interconnection 21of an Al-Si-Sn alloy or an Al-Si-Sb alloy is replaced with anAl-Si-Sn-Ti interconnection layer 20. In addition, the manufacturingprocess in the embodiment shown in FIG. 6 is the same as that in FIGS.5A to 5D except that interconnection materials are different from eachother.

In the present embodiment, the content of silicon in an interconnectionmaterial of an Al-Si-Sn-Ti alloy is maintained at approximately 0 to0.8% by weight in order to prevent deposition of silicon 8 in a contacthole portion 4 and deposition of a silicon nodule 9 in theinterconnection layer in heat treatment at a temperature of 400° to 500°C., as in the above described embodiment. In such a case, silicon in animpurity diffused layer 2 is soluble in the interconnection layer, sothat an alloy pit 11 occurs. Thus, in order to decrease the solidsolubility of silicon in the interconnection layer, any of tin, carbonand lead in the same group, in the periodic table, as that of siliconconstituting the semiconductor substrate 1 is added. On this occasion,the content of tin or the like in the alloy is selected to beapproximately 0.2 to 2.0% by weight, depending on the content ofsilicon.

Additionally, in order to prevent stripping in the interface of theinterconnection layer in an aperture 7 in a bonding pad region and anunderlayer insulating film 3 and improve adhesion, titanium the contentof which is approximately 0.05 to 1.0% by weight is added to the alloy.Since titanium has very strong bond force to oxygen, adhesion of anoxide film system such as a PSG film to the underlayer insulating film 3can be considerably improved. More specifically, an interconnectionmaterial of an Al-Si-Sn-Ti alloy is used as an interconnection layer 2D,occurrence of the alloy pit 11, deposition of the silicon 8 into thecontact hole portion 4 and occurrence of the silicon nodule 9 which wereproblems in the conventional example can be effectively prevented andadhesion of an oxide film system such as the PSG film or the like to theunderlayer insulating film 3 can be improved.

Although in the above described embodiment, description was made of acase in which titanium is added to the Al-Si alloy, it should be notedthat the present invention is not limited to the same. For example,vanadium and chromium having strong bond force to oxygen like titaniummay be used.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

What is claimed is:
 1. A semiconductor device comprising:a semiconductorlayer having a predetermined element as a constituent element thereof,an impurity diffused layer formed in a predetermined region of saidsemiconductor layer of said semiconductor device, and an interconnectionlayer of an aluminum alloy film having aluminum as the major constituentand formed on at least said impurity diffused layer so as to receive andsend electrical signals form and to said impurity diffused layer, saidinterconnection layer o the aluminum alloy film including at least oneelement in elemental form from a first group consisting of carbon, tinand lead which is different from said predetermined element, the contentof said at least one element in said interconnection layer defined as y,said interconnection layer of the aluminum alloy film further includingsilicon, the content of silicon in said interconnection layer defined asx, wherein x is selected to satisfy 0<x<0;8 wt. %, y is selected tosatisfy 0.2 wt. % <y<2.0 wt. % and x+y<2.0 wt. %.
 2. The semiconductordevice according to claim 1, whereinsaid semiconductor layer is formedof silicon.
 3. The semiconductor device according to claim 1,wherein,said interconnection layer of the aluminum alloy film comprisesat least one type of element chosen from the second group consisting oftitanium, vanadium and chromium.
 4. The semiconductor device accordingto claim 3, whereinthe total amount of said element of said second groupis z and z is selected to satisfy 0.05>z>1.0% by weight.